This invention relates to an endodontic stop positioner with a positioning member and a wire intersectingly disposed in connection with a reamer or file movably held in the positioning member during endodontic therapy so as to clearly indicate the root canal length of the tooth in an X-ray film.
It is generally known that a human tooth as shown in FIG. 1, consists of pulp chamber 10, root canal 11, enamel 12, dentin 13, and cementum 14 wherein the pulp chamber 10 and the root canal 11 are composed of nerve tissue and blood vessels. Therefore, when the tissue of the pulp suffers from traumatic injury, caries and periodontal infection, inflammation or necrosis of the pulp tissue will occur. Consequently, an endodontic therapy generally called "root canal treatment" is necessary for this tooth. The main work required for the endodontic therapy is to thoroughly remove the inflammed or necrotic pulp tissue, and then to seal up the root canal with aseptic material. Since the kind of treatment is delicate work and has to be done within the inner part of a tooth, a radiographic diagnosis is usually relied upon to assist in completing the treatment. In order to successfully perform the endodontic therapy, the root canal length of the involved tooth must be exactly measured before the root canal is sealed up. Accordingly, the most important work in endodontic therapy is to measure the exact root canal length of the tooth because only when debridement is performed completely in the tooth can the root canal be sealed up thereat.
Concerning the measurement of the root canal length, various methods are adopted in endodontic therapy, and one of the frequently used methods is X-ray, for which a reamer or file 20, as shown in FIG. 2, is inserted into the root canal, and then an endodontic stop 30a movably attached to the reamer or file 20 is adjusted to have its bottom surface kept in contact with the incisal edge or the cusp tip of the tooth for being X-rayed thereat. In this condition, the intersection between the endodontic stop 30a and the reamer or file 20 in the root canal will be shown in the X-ray film so that the root canal length can be measured from the reamer or file 20.
A conventional endodontic stop is usually made of either metal or non-metal materials and is formed in a plate shape as shown in FIG. 3 wherein the endodontic stop 30b is a metal one. As the reamer or file 20 is made of metal material, the intersection point of the reamer or file 20 and the endodontic stop 30b appears as a blur in the X-ray, making it difficult to exactly estimate the root canal length. On the other hand, as a non-metal endodontic stop can be penetrated by the X-ray, no clear intersection point between the endodontic stop and the reamer or file can be seen in the X-ray film, particularly when the X-ray is taken at an inclined angle. As shown in FIG. 4, the endodontic stop 30a and the reamer or file 20 appearing in the X-ray intersect in an area rather than at a point, resulting in difficulty in determining the length of the root canal measured therewith.